Dental apparatus and method of use

ABSTRACT

A tray for making dental check bite records is provided with a U-shaped bite section and a raised central arch. The tray is formed of stiff but deformable metal, which is perforated in the bite section to facilitate the adherence of dental impression paste. A flange on the front of the tray facilitates centering of the tray in the patient&#39;s mouth, and serrations on the edges of the tray provide convenient gripping areas when handling the tray. A check bite record is made with each tray. After first hardening an impression of the upper teeth on the tray, a glob of quicksetting impression material is positioned on the lower side of the tray to register on a lower anterior tooth. The impression in the hardened glob is then used as a pivot point to position a patient&#39;s jaw, while slower setting material is on the tray lower surface is hardening, providing an impression of the patient&#39;s lower posterior teeth in a preferred lateral position. 
     These check bite records are then used in combination with dental casts mounted in a dental articulator to properly set the articulator in a manner to simulate the patient&#39;s jaw movements while observing the construction of the dental cast and analyzing jaw movements. Novel selector elements are mounted in the upper frame of the articulator while using the lateral check bite records, with the selectors being used to measure lateral side shift and angular orientation. This information is utilized to select a proper set of preformed analog guide blocks to use in the articulator.

This application is a continuation of application Ser. No. 580,071,filed Feb. 14, 1984, now U.S. Pat. No. 4,543,062 issued Sept. 24, 1985.

BACKGROUND OF THE INVENTION

This invention relates to improved apparatus and methods for use indiagnosing dental occlusions and in making and testing dental prostheticdevices outside of a patient's mouth.

The making of artificial teeth or other prosthetic devices is still, toa large extent, a trial and error technique. The desired goal is to makethe necessary impressions and measurements on the patient's teeth andjaw and then make the prosthetic device and test it, without the need tosee the patient until the device is ready to be fit into the patient'smouth. To accomplish this goal, one common approach is to mount theprosthetic device in a dental articulator and attempt to simulate thepatient's jaw movements while observing whether the prosthetic deviceseems to be correctly designed. It therefore becomes necessary to beable to properly set or adjust the dental articulator so as to bestsimulate the patient's jaw movements.

One common technique for doing this is to make records of the patient'steeth with the jaws in various positions and then attempt to transferthe recorded information to the dental articulator. This approach isoften referred to as the "checkbite" procedure wherin the patient bitesinto impression paste, wax or plaster, and attempts are made to maintainthe patient's jaws stationary while the paste, wax or plaster sets orhardens. Simple, flat, metal sheets have been used to hold theimpression material in some techniques.

This general approach is accomplished in several different ways, all ofwhich have various advantages and disadvantages. A common advantage ofthis technique is that it is readily understandable and thus teachable,at least in concept, which is in contrast to some methods of making jawmeasurements and setting dental articulators. On the other hand, acommon disadvantage of the prior known checkbite approaches is that theyare inaccurate due to improper understanding of lateral jaw movement andimproper techniques, such that the mandible posterior teeth are notproperly positioned when impressions are made. Further, with the methodsused, it is difficult to maintain the patient's lower jaw steady whiletooth impression material is hardening, and thus, difficult to obtainthe desired accurate results. Thus, a need still exists for improvingthe apparatus and methods of simply obtaining accurate check biterecords used in setting a dental articulator.

SUMMARY OF THE INVENTION

A primary component of the system of this invention is an improved checkbite element for obtaining a record of the patient's jaw movements whichis used for facilitating the testing of a dental prosthesis in a dentalarticulator. This element includes a plate or tray shaped to fit withina person's mouth between the upper and lower jaw. The tray has agenerally U-shaped bite section to be positioned between the upper andlower teeth and preferably includes a raised central arch within theU-shaped bite section that fits within the arch of a person's upper jawso as to help position the plate. The tray bite section is preferablymade of a thin material which is stiff but is nevertheless deformablewhen clamped between the person's upper and lower teeth so that apartial impression is made of the teeth in the bite section. Preferably,the plate is stamped as a unitary element.

It is desirable that the tray bite section be formed with a plurality ofperforations so that impression paste applied to the bite section willtend to be anchored thereby with the paste extending into the holes. Thetray is further preferably provided with a short upwardly extendingflange on its anterior edge to facilitate the proper positioning of theplate within the patient's mouth. Also, the flange may be formed withsuitable markings to help center the tray in the patient's mouth and toindicate lateral movement of the lower jaw. The tray is furtherpreferably formed with serrations or other gripping means on the sideedges so as to make it easier for the operator to grip the tray wheninserting or withdrawing it from the patient's mouth.

In accordance with a method of the invention, the improved check bitetray is initially inserted into the patient's mouth and the patient isinstructed to bite into the tray bite section. This causes the traymaterial to deform somewhat making a partial impression of the patient'supper and lower teeth. The tray is then removed from the patient's mouthand dental impression material or paste is applied to the bite sectionof the plate. After an impression has been made and the material hashardened, a small quantity of a soft but quicksetting compound isapplied to the bottom side of the tray bite section in the area of alower tooth which is to be used as a guide in making a check biterecord. For example, in making a side shift record, the compound ispreferably placed in an area to be engaged by one of the lower canineteeth, and the tray is reinserted into the patient's mouth with theupper teeth in registry with the hardened impression on the upper sideof the plate. The lower jaw is then shifted laterally and lightly closedso that the lower reference tooth is pressed partially into the soft butquicksetting compound. The tray is then removed; and additionalimpression paste is applied to the remainder of the lower surface of thebite section of the plate.

The tray is then reinserted into the mouth in registry with the upperteeth, and the jaw moved laterally into position wherein the referencetooth engages the indexing impression in the now hardened quicksettingcompound. Using the hardened indexing impression as a fulcrum to supportthe canine teeth in a fixed selected position, the operator induces fulllateral movement of the mandible by pushing laterally on the rearangular portion of the mandible. Immediately, the condyle moves intofull border movement position sometimes called "Bennett movement" orside shift. It is this position which should be recorded. In inducingsuch movement, the other lower teeth are, of course, pressed into theimpression paste. The mandible is held in this predetermined position,guided by the hardened index until the impression paste is set,preferably, completely hardened. The tray is then removed having thedesired check bite record.

A similar check bite record is then made for the side shift bordermovement in the opposite direction by using the other lower canine toothas a reference point.

Using the lower incisors as reference teeth, a protrusive record mayalso be made, but this is not so critical in that the patient can movehis jaw into the desired position. Also, a centric check bite recordcan. be made with the use of the hardened compound, however, this is aknown technique.

When the check bite reference records are to be used in setting thedental articulator, previously made dental casts of the patient's teethare placed into a dental articulator with the centric check bite recordbeing used in a known manner to properly position the dental casts incentric position. The lateral check bite records are then used to setthe boundaries of the lateral movement of the articulator frames. Tomeasure this movement in a manner useful in selecting appropriate analogblocks which will guide movement of the articulator frames, a specialpair of measuring selector elements are mounted in the upper frame ofthe articulator. They are provided with an opening for receiving thestyluses or condyle-like elements on the lower frame of the articulator.The guides are provided with suitable means for tracking the lateralmovement of the frames when they are-placed in the left and rightposition as determined by the check bite plates. These measurements arethen utilized to select the proper guide blocks for the articulator froma supply of preformed guide blocks which are then mounted in the frameof the articulator replacing the selector elements. In this manner, thearticulator is set so that the full range of movement simulting thepatient's jaw movement may be obtained. These selector elements, thus,also form important components of the invention apparatus.

SUMMARY OF THE DRAWINGS

FIG. 1 is a perspective view of the top side of the check bite tray ofthe invention.

FIG. 2 shows the tray after it has been compressed between the patient'steeth.

FIG. 3 shows the upper surface of the tray with dental impression pasteapplied to the upper surface of the tray bite section.

FIG. 4 is a lower perspective view of the tray.

FIG. 4a is a perspective view of the lower side of the tray with aquantity of quicksetting compound positioned on one side of the checkbite section, and FIG. 4b is a similar view showing a quantity of thecompound positioned on the other side of a different check bite tray.

FIG. 5 is a schematic cross-sectional view of the tray of FIG. 4ainverted in a patient's mouth, when viewed on line 5--5, illustratingthe manner the patient's lower right canine tooth is positioned in someof the quicksetting compound with the mandible shifted laterally so thatthe upper and lower canine teeth are approximately aligned.

FIG. 6 is a perspective view of the lower surface of the tray in FIG. 5after an impression of the lower right canine has been made.

FIG. 7 is a perspective view of the lower surface of the tray of FIG. 6after impression paste has been positioned on the remainder of the bitesection of the lower surface of the tray.

FIG. 8 is a perspective view of a dental articulator supporting a pairof dental casts, with a check bite record between them.

FIG. 9 is a top perspective view of a guide block element.

FIG. 10 is a bottom perspective view of the selector of FIG. 9.

FIG. 11 is a fragmentary perspective view of the right selector mountedin the articulator and engaging the medial side of the condylar element.

FIG. 12 is a fragmentary perspective view illustrating the Bennett scalebeing manipulated to provide a reading of side shift measurement andangular orientation.

CHECK BITE TRAY

Referring first to FIGS. 1 and 4, the check bite element of theinvention comprises a thin tray or plate 10 sized to fit within aperson's mouth. The tray includes an outer U or V-shaped bite section 12enclosing an upwardly extending arch. The bite section 12 is sized tofit between the patient's teeth while the arch mates with the arch of aperson's upper jaw to properly position the plate.

Formed in the bite section 12 is a plurality of small holes orperforations 16, which facilitate the attachment of tooth impressionpaste to the plate. As may be seen, there is an inner and an outerU-shaped row of holes 16, with the rows being offset so that the holesin one row are midway between the holes of the other row. Thisarrangement provides adequate anchoring points, but minimizes thelikelihood of a tooth cusp engaging a hole. Further, the holes aresmaller than a tooth cusp so that a cusp cannot penetrate the tray.

Formed on the outer edge of each side of the bite section is a series ofinterruptions or serrations 18 which serve as means to facilitategripping of the plate, while inserting or removing it from the patient'smouth. The tray edge is slippery and smooth such that it is difficult tohold the tray without suitable gripping means.

A short, vertically extending flange is formed on the anterior orforward edge of the central part of the bite section 12. The flange 20extends laterally a distance about equal to the width of two or threefront teeth. The forward exterior surface of the flange 20 is formedwith a series of vertically extending grooves or lines 21 to serve asguides for centrally positioning the tray within a patient's mouth, andto gage mandible side shift.

The check bite tray 10 is relatively thin (preferably no more than onemillimeter), being made of stiff metal which is yet sufficiently soft ormalleable that it can be deformed by the patient's teeth to a limitedextent when tightly gripped by the teeth. It is desirable that thematerial be thin and malleable so that the teeth are almost closed whenimpressions are made. It is, of course, necessary that the materialemployed be acceptable from a health standpoint. In one suitableexample, the tray is made of dead-soft, anodized aluminum and has athickness of about 0.5 millimeters. The tray arch serves to center thetray in the patient's mouth and also acts as a siffener for the thinmaterial. Preferably, the tray is stamped from flat stock in a multipledie operation. Stamping the tray stiffens the material in the side ofthe arch, while leaving the flat bite section dead-soft.

METHOD OF MAKING CHECK BITE RECORDS

In use, the check bite trays may be employed to make a record ofwhatever relationship between the jaws is desired. Typically, however, acheck bite record is made of the jaws in centric relation position, andin the left and right extreme lateral positions. The centric relationposition is that in which the mandible is centered with respect to themaxilla, and the mandible is held in its rearward-most or fully retrudedposition. The left and right lateral positions are those in which thelower jaw is moved laterally to its extreme left or right positions,illustrating the so-called Bennett movement or side shift. The initialsteps of the procedure are the same for all of the check bite recordsusually made.

The tray is gripped by the thumb and index finger at the serrated edges18, as the tray is inserted into the patient's mouth with the forwardflange 20 resting against the labial surface of the incisors. The trayis centered laterally by aligning the midline mark of the lines 21 onthe flange with the midline of the teeth. If the tray is too long forthe patient's mouth, the rear edge may be cut with sharp scissors andthe edges sanded.

The tray is then repositioned in the patient's mouth and the patient isinstructed to bite down hard on the tray several times to deform it tofit closely between the teeth. When the tray is removed, it appearssomewhat as illustrated in FIG. 2 with tooth impressions or indentations23 shown in the upper surface. The tray should then be dried withcompressed air and both sides of the bite section 12 painted or sprayedwith a suitable material, such as a quick-drying varnish.

A small amount of zinc oxide and euginol, bite registration paste 22 isspread thinly (about 1 millimeter thick) over the upper side of the traybite section 12. The tray is then repositioned in the patient's mouthand held in place lightly against the maxillary teeth. The patientshould be instructed to tap the teeth together to assure that the trayis properly repositioned. Note that the indentations 23 made earlierassist proper alignment. The patient's mouth should then be held openslightly to keep the lower teeth away from the lower side of the traywhile the operator holds the tray lightly against the upper teeth untilthe paste hardens.

The tray is then removed from the patient's mouth and excess material onthe upper side is trimmed away with a sharp scalpel leaving onlyimpressions of cusp tips. Loose material may be removed with compressedair. The holes or perforations 16 in the bite section 12 of the traycause the paste to extrude into the holes to help anchor the material,and some paste flows onto the lower side of the tray. With scalpel orcotton pliers, any such excess paste that might be projecting from thelower side should be removed. The tray should then be reinserted intothe patient's mouth to assure proper fit to the maxillary teeth.

The tray is then removed once more and dried with compressed air beforepositioning a small amount of soft, quicksetting material onto a desiredportion of the lower side of the bite section of the tray. A verysuitable material is the familiar dental compound, in the nature ofsealing wax. This compound softens when heated but quickly hardens atroom temperature. It will soften again when reheated.

For making the left and right lateral check bites, it is desirable thatthe glob of material be placed in an area to be contacted by a lowercanine tooth on one side of the jaw. This glob is shown at 26 in FIG. 4afor one side and at 28 in FIG. 4b for the opposite side on a secondtray. Although a separate tray is required for the left lateral recordand for the right lateral record, the trays are numbered the same in thedrawing for convenience, even though they represent different trays.

While the quicksetting material is still warm and pliable, the tray isreplaced in the patient's mouth and placed in registration with themaxillary teeth. The patient should be instructed to wet with saliva thelower teeth to be engaged. The tray should be held to the upper teethwith the thumb and index finger of one hand while the thumb of the otherhand holds the patient's lower lip away from the teeth. The end of thesame thumb may be held against the labial surface of the lower teeth.

In making a right lateral record, the patient, with his mouth partiallyopen, should be instructed to shift his lower jaw to the right so thatthe lower right canine tooth is approximately aligned with the upperright canine tooth. This is usually a lateral movement of the forwardportion of the lower jaw about three millimeters. This may also be gagedby vertically aligning one of the outer lines 21 on the tray flange withthe midline of the lower jaw or a spot marked on a lower incisor toindicate a three millimeter shift. The operator gradually aids thepatient in decreasing the vertical dimension until the lower caninetooth 25 (FIG. 5) just contacts the soft compound 26 without theposterior teeth touching the bite tray. As soon as the canine tooth 25touches the compound 30 and makes a light impression 24, as seen in FIG.6, the patient should be instructed to open his mouth. After this index24 of the lower canine tooth has been made in the compound, the tray isremoved and the compound allowed to harden, which it does very quickly.The excess compound can then be cut away so that only the tip of thecanine tooth can be seen (preferably no more than 1/2 millimeter deep inthe compound).

The tray as seen in FIG. 6, should then be placed back into thepatient's mouth to verify that forward portion of the mandible wasshifted sideways about three millimeters when the index was formed.Marking ribbon may be used to check for the absence of contacts of thelower posterior teeth with the tray. If there is contact, more compoundmust be added to increase the vertical dimension and the impressionsteps repeated.

A thick layer (about three millimeters) of bite registration material orpaste 31, as seen in FIG. 7, is then applied to the bite section 12 ofthe lower side of the tray and the tray is placed back into the mouth inregister with the upper teeth. The mandible is then moved laterally andupwardly into position wherein the cusp of the reference canine tooth 25fits into the index 24 in the Hardened compound 26. Using the indeximpression as a fulcrum to support the canine tooth 25 in the fixedselected position, the operator simultaneously induces full lateralmovement of the condyle area of the mandible by pushing laterally on therear of the mandible. This immediately moves the condyle into fullborder or side shift movement position, which is the predeterminedposition desired to be recorded. The patient is instructed to hold thelower teeth in the impression paste with the lower canine 25 in theindex 24 without clinching pressure until the bite paste hardens, whilethe operator continues to hold the rear mandible in the full side shiftposition. Hardening usually takes one to two minutes.

It is important to realize that the patient cannot move his jaws byhimself into the desired predetermined lateral postion of full condyleborder movement. If the patient were asked to move the mandible into afull lateral side shift position, the condyle area will usually tend tomove in a relatively straight line forwardly and laterally, whereas withmost patients, the condyle area can be shifted laterally more quicklyand will move in a curved path laterally and forwardly. The patient'smandible will reach that full side shift position during certain normalchewing functions, such as while chewing dense food products, eventhough the patient cannot move the mandible in that manner when objectsare not being chewed. This has to do with the person's chewing musclesand brain signals.

The value of the index can also be appreciated at this stage from thestandpoint that the patient would not be able to hold the jawssufficiently steady while the paste hardens without having the benefitof the index. It is important that the patient not bite hard while theregistration paste is setting so that the lower jaw is being positionedsolely by the index 24.

It is necessary that the paste 31 be somewhat thicker than the compound30 between the tips of the tooth 25 and the tray bite section 12, sincethe lower teeth remain spaced from the tray bite section. The spots ofhardened material in the holes 16 on the lower side of the tray bitesection 12 help anchor the paste 31 to the tray. After the paste is set,the tray is removed from the patient's mouth and with a sharp scalpel,the excess paste is cut away on the lower side until only the cusp tipsremain.

The procedure then may be repeated with another tray for a left lateralcheck bite record. The procedure is basically the same except that themandible is held in the opposite side shift position or the protrusiveposition when the indexing or guide impression is made, and the lowercanine tooth on the opposite side is used to make the record of theother lateral shift.

A protrusive check bite record may also be made by the two-stepapproach, using the lower incisors as the indexing teeth. However, thepatient can move his jaw into the protrusive position using his jawmuscles. Thus, there is no operator induced lateral movement wherein thehardened compound is being used as a fulcrum.

A centric check bite record is needed to initially position dental castsin an articulator. Again, the lower incisors are used for indexing, butthe index does not form a fulcrum for operator induced movement aboutthe fulcrum. The operator does, however, assist in moving the mandibleto its fully retruded position in making the index in the quicksettingcompound. The casts of the patient's teeth that have been previouslymade may be checked with the registrations on the tray to see that theyaccurately fit into the record before mounting on an articulator. It isconvenient to store the casts with the centric relation recordpositioned between the teeth.

Use of the two different materials and the two-step process in makingthe impressions on the lower teeth provides the necessary accuracywithout the need for great skill. The registration paste of zinc-oxideand eugenol is excellent for making check bite records because it doesnot shrink and it is quite strong, but is not brittle. Also, it adheresquite well to the metal tray. It is suitable for use in a patient'smouth and is reasonably priced. Unfortunately, it does not hardenquickly enough such that a patient can hold his jaw steady as thematerial hardens.

The sealing wax dental compound hardens quickly but it is relativelybrittle and shrinks somewhat. It is suitable for indexing but notsuitable for making the impression of all of the lower teeth at onetime.

USE OF CHECK BITE RECORDS WITH A DENTAL ARTICULATOR

FIG. 8 illustrates a pair of dental casts 30 and 32 supporting a checkbite record tray 10 between them. The dental casts are shown mounted ina dental articulator 38 having an upper frame 40 which support a pair ofguide blocks (not shown) that cooperate with a pair of condyle-likeposts or styluses 44 mounted on a lower frame 46. The frames arepivotally mounted to each other with the movement being guided by guideblocks (not shown) mounted on the upper frame which slides and pivotswith respect to the styluses. Guide blocks of average value sizes areavailable from which the operator may choose to best simulate thepatient's jaw movement. These guide blocks are removably mounted inholes in the upper frame. Known means (not shown) is also provided forlocking the frames to hinge only in centric position. Further details ofsuch an articulator and such guide blocks may be seen in U.S. Pat. Nos.4,034,474 and 4,034,475, which are incorporated herein by reference.

The dental casts 30 and 32 are shown connected by plaster to an uppermounting plate 49 and a lower mounting plate 48 which, in turn, arerespectively mounted to the upper and lower articulator frames 40 and46.

The purpose of mounting the dental casts 30 and 32 in the articulator isto enable the operator to move the articulator frames in a manner tosimulate the movement of the patient's jaw movement so as to observe themovement and the fit between the artificial teeth. This procedureminimizes the time required to actually fit the artificial teeth in thepatient's mouth. The purpose of the check bite records is to positionthe dental casts in the border positions in the articulator so thatguide blocks of the desired type may be selected to provide movementwithin the limits determined by the check bite records. The centriccheck record is used in a known manner in properly mounting the dentalcasts to their mounting plates. The dental casts, while gripping thecentric check bite record, are supported for a suitable fixture (notshown) between the upper and lower articulator frames. The casts arethen plastered to the mounting plates 47 and 48, while the plates arefixed to the articulator.

The lateral check bite records are then used to hold the articulatorframes in the lateral position. To assist in the process of determiningwhich guide blocks to select, there is provided a pair of guide blockselectors which replace the guide blocks when the check bite records arebeing used. Such a guide block selector 50 is shown in FIGS. 9 and 10.The left selector is shown for purposes of illustration, but the rightselector is the same, only reversed. The numbers refer to either a rightor a left selector. As may be seen, the selector 50 includes a small,generally rectangular block-like body or element 52, connected to amounting pin 54 that mounts in the dental articulator in the same holein which a guide block is mounted when the articulator is being used tosimulate jaw movement. In the lower surface of the element, there isprovided an opening 56 for receiving a stylus 44 on the lower frame ofthe articulator. A slot 58 in the upper wall of the element 52 opensinto the opening 56 in the lower surface of the element. The elongatedslot 58 extends generally perpendicular to the pin 54, with the leftinner edge of the slot, as viewed in FIG. 9, being flush with the inneror medial wall 56a of the opening 56.

Also formed in the upper surface of the selector element 52 is ahorizontally extending groove in which is slidably positioned ahorizontally movable pin 60, which may be referred to as a Bennettscale, inasmuch it is used to measure side or lateral movement. Smallcalibration lines 62 are formed on the upper side of the Bennett scale,generally perpendicular to the mounting pin 54 and alignable with areference line 64 on the adjacent upper surface of the selector element.This line 64 is in the same vertical plane as the medial wall 56a.

As indicated above, the analog selectors are used with the lateral checkbite records. As shown in FIG. 8, the guide blocks have been removedfrom the upper frame of the articulator and the right analog selector 50is mounted in the right side of the upper frame of the articulator. Notethat left and right refer to the orientation that it would be for thepatient. Thus, if the dental casts shown in FIG. 8 were assumed to be ina patient's mouth, the right side of the patient's jaw, as viewed fromthe patient's perspective, is where the right analog selector ispositioned. From the perspective of the viewer in FIG. 8, the rightanalog selector is on the left. The selector 50 should be transverselypositioned, initially, against the calibrated side 47 of the upper frame40 of the articulator. The selector should be rotated to its maximumupper position so that the walls of the selector opening 56 are notengaging the stylus 44. The set screw 55 (FIG. 11) is then tightenedagainst the mounting pin 54 to hold the selector in that position.

The centric check bite record has been removed and replaced by the leftlateral check bite record being carefully positioned onto the lowerdental cast 32. Note that the left check bite record is used with theright selector 50 so as to obtain the best balance. The upper frame 40of the articulator is then carefully lowered to register the teeth ofthe upper dental cast 30 with the tooth impressions in the upper surfaceof the check bite plate. Assuming that the patient had some left lateralmovement, it will be necessary to laterally slide the upper frame of thearticulator a slight amount and probably move it forwardly so that theupper teeth will align properly.

With the upper dental cast firmly positioned into the check bite record,there will be space between the stylus or condyle 44 and the walls ofthe opening 56 in the analog selector 50. While pressing the maxillarycast firmly downward into the check bite, the mounting screw 55 holdingthe selector pin 54 should be loosened allowing the selector to pivotdownward to contact the upper surface of the stylus.

The selector 50 should then be pulled outwardly, laterally so that themedial wall 56a of the selector opening 56 engages the medial side ofthe stylus 44. This condition is shown in FIG. 11. The selector 50 islocked in this position by tightening the thumb screw 55 against themounting pin 54.

The Bennett scale 60 is then pushed inwardly or medially until ittouches the calibrated side 47 of the articulator frame 40, as shown inFIG. 12. The amount of Bennett movement is read in millimeters on thesmall scale 62. If the scale line 62a on the extreme left is alignedwith the reference line 64 on the upper surface of the selector, therewould be zero side shift. The line 62a may be provided with a zeromarked thereon to facilitate reservation. For the patient in FIG. 12,the second scale line 62b is aligned with the reference line 64. Thisindicates that the patient has one millimeter of Bennett or lateral sidemovement. Therefore, a performed analog or guide block having a onemillimeter side shift capacity is to be used on this side of thearticulated frame to guide the movement of the upper frame with respectto the lower frame. As indicated above, the analog block is selectedfrom a supply of blocks having performed openings of various sizes.

The desired angular inclination for the selected analog guide block isread by observing where the end of the Bennett scale 60 touches thecalibrated side 47 of the articulator frame 40. For the teeth of thepatient illustrated, this appears to be an angular inclination readingof about 7. Thus, when the selector 50 is removed and replaced by ananalog guide block, the block is similarly oriented to the number 7position. The upper surface of the selector has the same relation to itsmounting pin as does the guide block to its mounting pin.

The above procedure is then repeated to select the left side analog.That is, the left side selector 50 shown in FIG. 10 is mounted in theupper articulator frame engaging the other calibrated side of the frame40, and the patient's right lateral check bite record is positionedbetween the dental casts. It should be recognized that the patient'sleft and right lateral movements are not necessarily the same and thusthe left side might require a side shift greater than the other, forexample. This completes the selection process and the operator can nowproceed with the movement of the articulator frames to simulate thepatient's jaw movements, and thereby test the adequacy of the dentalcasts.

It should be noted that while there are many steps to the procedure ofmaking the check bite records and utilizing them to set the articulatorframes, the steps are all relatively simple and require little judgmenton the part of the operator. This is of great significance in that itenables an operator to be quickly trained, and enables personnel otherthan dentists to perform the procedures. Related to this, the apparatusand supplies required are relatively inexpensive. That is, the checkbite trays are mass produced with the desired shape and configuration.The impression paste and the quick setting materials are also relativelyinexpensive. While the precision made left and right selector elementsintroduce some expense, only a single set is required, since they areusable for all patients.

I claim:
 1. A dental check bite element comprising a tray shaped to fitwithin a person's mouth between the upper and lower teeth, the trayhaving a peripheral bite section to be engaged by the upper and lowerteeth, said bite section being made of a thin material and havinggenerally smooth lateral edges which curve towards the front of the trayto conform to a person's mouth, said lateral edges being interrupted toform means to facilitate gripping said edges with the thumb and a fingerof one hand when inserting or withdrawing the tray from a patient'smouth.
 2. An element of claim 1 wherein said tray bite section is madeof thin material which is stiff but deformable by a person's teeth whenclamped between the upper and lower teeth. PG,22
 3. The element of claim1 wherein said gripping means comprises a serrated section on each ofthe two opposite lateral edges.
 4. The element of claim 3 wherein saidserrated sections are located in an area where the lateral edges curvetowards the front of the tray.
 5. The element of claim 1 wherein saidgripping means are located on each side of the tray in the area to beengaged by the patient's bicuspids.
 6. A dental check bite elementcomprising a tray shaped to fit within a person's mouth between theupper and lower teeth, the tray having a peripheral bite section to beengaged by the upper and lower teeth, the tray being made of thin metalwhich is stiff but deformable when clamped between the person's upperand lower teeth so that a partial impression is made of the teeth in thebite section, the lateral edges of the forward portion of the bitesection being curved to generally conform to the shape of the forwardportion of a person's mouth, and serrations formed in the lateral edgesof the tray on each side of the tray in the curved forward portiongenerally laterally outwardly from the portions of the bite section tobe engaged by the person's bicuspids.